Bouveret Syndrome: Etiology, Clinical Presentation, Differential Diagnosis, Complications, and Treatment Options

Bouveret syndrome is one of the complications of gallstone disease possibly fatal, which proposes the presence of a large stone obliterating the lumen of the duodenum or stomach because of the formation of a bilioenteric fistula. This review article, therefore, plans to review the causes, patient characteristics, diagnostic workup, associated conditions, and treatment of Bouveret syndrome. A literature search was also performed through scientific databases such as Scopus, Google Scholar, and PubMed concerning articles related to Bouveret syndrome written by different authors. The terms employed for the search were bilioduodenal fistula, Bouveret syndrome, gastric outlet obstruction, and gallstone ileus. Both case reports and systematic reviews that were written in the English language and published between the years 2000 and 2024 were considered. Finally, the review establishes the relevant concerns surrounding the diagnosis of Bouveret syndrome, focusing on the diagnosing issues. It emphasises the need for some specialities' involvement and focuses on the importance of endoscopic intervention. For patients, endoscopy remains the first line of treatment, while surgery is necessary in cases where conservative methods cannot be used. The article also focuses on new approaches to treating the conditions, such as percutaneous gallbladder stone dissolution. Latterly, further developments in minimally invasive surgery pertain to refining methods, including endoscopic removal and lithotripsy, to improve the survival rate of patients. Further investigation is required, especially regarding the administration schedule in relation to this disorder and goals that can reduce mortality and morbidity, especially in elderly patients with comorbid diseases.


Introduction And Background
Gastric outlet obstruction is the trademark of the exceptional gallstone disease condition known as Bouveret syndrome [1].This uncommon gallstone ileus is caused by a vast stone impaction within the proximal duodenum or pylorus due to an unconstrained fistula between the stomach or duodenum and the gallbladder [2].M. Beassier, a French specialist, was the primary to depict it preoperatively in 1770 [3].Afterwards, this sickness was called for by the French doctor L. Bouveret, who distributed two careful case reports of it in 1896 [1,4].The critical passing rate related to Bouveret syndrome, generally 12-30%, is ascribed to the disease's complexity, non-specific presentation, and tendency to influence older adults [5].Besides, there's no agreement around the diagnostic workup and administration counting endoscopy, laparoscopy, and open surgery due to the disease's rarity [6].An enormous stone that blocks the stomach outflow and voyages through a bilioduodenal fistula is the cause of Bouveret syndrome [7].Due to nonspecific indications and laboratory results, there's a significant hazard of misdiagnosing Bouveret syndrome [4,8].Bouveret syndrome is the foremost exceptional kind of gallstone ileus [7].It happens when a gallstone relocates using a bilioenteric fistula, obstructing the gastric outlet and, in uncommon events, other parts of the digestive tract [8,9].The entrance location is, as a rule, a fistula between the gallbladder and a segment of the stomach or digestive system [10].A history of cholelithiasis, stones larger than 2-8 cm, female, and older than 60 are among the risk factors [1,7].Key characteristics of Bouveret syndrome are described in Table 1.

Search methodology
A literature search was conducted for this review of Bouveret syndrome.The search was conducted using databases such as Scopus, Google Scholar, and PubMed.The MeSH terms and a few keywords used were bilioduodenal fistula, Bouveret syndrome, gastric outlet obstruction, and gallstone ileus.The articles were chosen for their relevance, timeliness, and availability of clinical information, pathophysiology, differential diagnosis, complications, and available treatments.Only peer-reviewed English-language articles were included, such as case studies and systematic reviews published between 2000 and 2024.The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram is shown in Figure 1.

Pathophysiology of Bouveret syndrome
Bouveret syndrome may be an exceptionally exceptional condition that accounts for 0.3-5% of complications from cholelithiasis and accounts for 1-3% of all gastrointestinal (GI) tract blockages brought on by gallstones [11].However, most stones are small and either pass undetected or have terminal ileum impaction [12].Inflammation and attachment of the gallbladder to the GI system may ensue from an acute cholecystitis episode [13].This can cause an ischemia tear of the adjacent gallbladder and enteric wall in addition to the mechanical strain that gallstones put on the gallbladder and the bowel wall [14].Gallstone passage is facilitated by this process, which intensifies the development of a fistula between the gallbladder and the colon [15].
In addition to acute cholecystitis, a few case reports resulting from gallbladder malignancy have been released, describing the development of a cholecystoenteric fistula [3,10,16].Comprising 68% of cases, bilioenteric fistulas typically manifest as cholecystoduodenal fistulas [17].Cholecystocolic and cholecystogastric fistulas are less frequent variations that comprise 17% and 5% of cases, respectively [17].
Due to the thickness of the stomach wall, cholecystogastric fistulas are most likely the rarest [18].Even with a bilioenteric fistula, most ectopic gallstones are removed by vomiting or diarrhea [9].In addition to other variables, such as pre-existing stenosis or changed GI tract anatomy following surgery, more giant stones are likely to cause clinical signs of gastric outlet obstruction [19].Clinical features of Bouveret syndrome are described in Table 2.

Differential diagnosis of Bouveret syndrome
Differential diagnosis of Bouveret syndrome includes a wide range of illnesses.A duodenal web, or membrane-like blockage within the duodenum, is one of the congenital causes [10].Erosive gastritis, which causes erosion and inflammation of the stomach lining, peptic ulcer disease, which is characterized by sores in the stomach or duodenal lining, and Crohn's disease, an inflammatory bowel disease that can affect any part of the GI tract, are examples of conditions that have an inflammatory cause [12,20].Multiple forms of cancer are among the malignant causes of Bouveret syndrome.Duodenal carcinoma develops in the duodenum, whereas gastric antral carcinoma begins in the stomach's antrum [21].Other potential malignant causes include ampullary carcinoma, which appears at the ampulla of Vater, the point where the bile and pancreatic ducts converge, and pancreatic carcinoma, a cancer of the pancreas [12,22].A further possible malignant cause of this illness is cholangiocarcinoma, often known as bile duct cancer [16,23].Every one of these ailments has the potential to cause a bilioduodenal fistula, which in turn exacerbates Bouveret syndrome [1,10].Differential diagnosis of Bouveret syndrome is shown in Table 3.

Complications and treatment of Bouveret syndrome
Untreated Bouveret syndrome can lead to persistent blockage of the gastric outlet, which can cause anorexia, dehydration, malnutrition, and abnormalities in electrolytes [2,17,24].Intestinal perforation is the most dangerous consequence since it can cause severe morbidities [25].Recurrent Bouveret syndrome, biliary infection, gallstone pancreatitis, and maybe even cancer are risks associated with leaving a fistula untreated [12,26].There is always a danger of bleeding and infection during surgery [23].Furthermore, the biliary tree may unintentionally be harmed by cholecystectomy, mainly if inflammation is present [4].
Complications of Bouveret syndrome are mentioned in Table 4.

Complication Description
Persistent   Currently, the first line of treatment for Bouveret syndrome is endoscopic intervention [27].Endoscopic retrieval is one form of minimally invasive therapy, along with mechanical, electrohydraulic lithotripsy, laser, and extracorporeal shock waves [27,28].When an endoscopic attempt fails, or no technical knowledge is available, surgical solutions may need to be explored in treating individuals with Bouveret syndrome [4,27].The surgical strategy involves performing an open gastrotomy, pylorotomy, or duodenotomy at or near the obstruction location [25,29].If moving an affected duodenal gallstone into the stomach is feasible, a gastrostomy may remove the stone [4].It's controversial if treating Bouveret syndrome requires a multi-step procedure that combines cholecystectomy and fistula repair [30].Due to their age and numerous comorbidities, the majority of patients are not good candidates for surgery [30].The treatment of Bouveret syndrome is shown in Table 5.

Treatment Description
Endoscopic intervention (preferred) First-line treatment.The future of Bouveret syndrome treatment Nevertheless, Bouveret syndrome treatment is transitional from typical open surgeries [4].Surgical methods are now being supplemented by endoscopic techniques, which can require fewer invasions of the body and prove to be more advantageous to the patients [31].Electrohydraulic lithotripsy, for instance, applies electrical energy to break up the obstructing gallstone within the duodenum so that it can pass through easily [31].However, it is accompanied by the disadvantage of causing some harm to the neighbouring tissues [31].The researchers are working closely to fine-tune such methods to enhance more efficient fragmentation of the stones and reduce the undesired implications [32].Another potential method is endoscopic retrieval through baskets and nets [32].The endoscopic retrieval approach needs particular dexterity to eliminate the stone completely [32].Nevertheless, researchers are investigating more developed instruments in terms of grasping and visualization modules to raise the success ratios of endoscopic retrieval [32].
Besides such developments, further treatment strategies for Bouveret syndrome might include percutaneous gallbladder stone dissolution [5,22].This method employs drugs that are applied topically on the skin and directly to the organ, which is the gallbladder, to dissolve the stones without surgery [22].Although its use in the management of Bouveret syndrome is still under research, percutaneous dissolution can eradicate the syndrome completely because it deals with the cause of the syndrome, which is gallstones, through a nonsurgical technique [31,32].Studies included in the article are mentioned in Table 6.

FIGURE 1 :
FIGURE 1: PRISMA flow diagram Figure created by Nikhil Thatipalli PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-Analyses

TABLE 3 : Differential diagnosis of Bouveret syndrome
blockage Blockage of the gastric outlet can lead to anorexia, dehydration, malnutrition, and electrolyte imbalances